The male pill is coming. It will change everything.

Summary: Scientists soon will start another round in the revolutions shaking society by producing a male contraceptive pill. The effects could be wonderful, improving family planning and helping reduce pollution and minimize climate change.

Prepare for the next drop in fertility
The average number of births per woman based on age-specific fertility rates.

Today almost a third of American couples rely on the man to prevent ill-timed or unwanted pregnancy, but for young men who may want a child in the future, the options stink. Condoms are the best means available to prevent STIs, but in any given year one in six couples relying on condoms will end up with an unplanned pregnancy. …Vasectomy is highly effective, but since reversal may not work, it’s not an option for men who don’t already have the family they want.

By contrast, “get it and forget it” methods for women drop pregnancy risk below 1 in 500, have bonus health benefits, and return normal fertility. When it comes to people being able to manage their fertility, we are a long way from gender equality.

The good news is that the last decade has brought increased understanding of male reproductive physiology and revealed potential new methods to safeguard against an ill-timed pregnancy. No single method will ever fit for everyone, but a variety of potential contraceptives (mechanical or pharmaceutical, shorter or longer acting, reversible or permanent, some enhancing libido or sexual function and some sexually neutral) could offer men real choices that fit their age, culture and lifestyle. Some may even have bonus health benefits like increasing energy and muscle mass or preventing balding.

…In the words of Aaron Hamlin at the Male Contraception Project, “It’s been 55 years since the Pill for women came to market in the United States. The Pill for men is long overdue.”

Tarico describes several promising lines of research — at least one of which almost certainly will work — and excellent links for more information.

What effect might this have? We can only guess at how many men might use their new veto on child-making (surveys suggest that half of men are willing to use it even now). My guess: the effect will be large, perhaps very large. The massive effect of the women’s pill was a surprise to society; the men’s will surprise as well.

A new world with fewer people

See the clear and fascinating graphs at the Our World in Data website, show how the fertility rate (TFR) has been falling rapidly since WWII, with improved contraceptive methods a major factor. Their spread to emerging nations, along with other aspects of modernity, continues even now. India’s TFR was 5.9 in 1960, falling to 2.5 in 2012. Keyna’s TFR was 8.1 in 1970, falling to 4.5 in 2012. Iran’s TFR was 6.5 in 1982, falling to 1.9 in 2012.

The world’s TFR is forecast to hit replacement level (now 2.3) in the middle of the 21st century, and hit 2.0 late in the century. That assumes no radical innovations in contraceptive technology.

What happens if men get access to an effective contraceptive pill? Even a moderate effect on fertility would pull replacement rate fertility a decade forward in time, so that the second half would have fertility rates far below replacement. That would be wonderful news for several reasons.

Earth’s population load drives war, pollution, destruction of habitats, and many of the ills we inflict on the world. The sooner and faster Earth’s population begins shrinking, the better.

A faster-than-expected decline in fertility could bring other benefits. Most of the climate nightmares that dominate the news headlines are based on RCP8.5, the worst of the four scenarios used in the IPCC’s AR5. It assumes slow technological growth (the last half of the 21st century will be, like the late 19th, relying on coal) and rapid population growth (at the high end of the UN’s 2014 forecast). The coal forecasts already look wrong. A male pill might void the population forecasts, voiding both of the foundational assumptions for RCP8.5 — putting our climate on track for a better future than the nightmares we are led to expect.

So let’s give the scientists working on the male pill our best wishes for fast success.

The phase 3 results are due this year (I don’t see anything yet on Google). If the results are positive (in the US about 2/3 pass their phase 3 trials), production will start after a lag to build the manufacturing capability.

Interesting. I imagine, however, that the effects on society will be far less pronounced than the effects of female means of contraception, simply because it is fertility in women that tends to drive overall population growth. Imagine you’ve got 100 fertile men and 100 fertile women, and 60 of the women adopt an effective contraceptive method; you then have only 40 women continuing to have children. But if 60 of the men–heck, if 99 of the men–adopt an effective contraceptive method and none of the women do, then you could have all 100 women continuing to become pregnant.